Batch adding black video at the end of multiple MP4

[sheeracali]

Hi, I have a giant list of MP4 wrapped MPEG-2 Videos. I need to add about 5 seconds of blank video to the end of every one. If I created a video that matches the codec, is there a program that could add this video to the end of every single MP4? Also, I wouldn't mind repacking to mkv if I cant find a program that will work with MP4 and I don't mind having to pay for one either. Thanks

[videobruger]

I don't know where you have the mp4 files but a batch file like

if not exist concat md concat
for %%g in (*.mp4) do (
echo file '%%g' > concat.txt
echo file black.mp4 >> concat.txt
ffmpeg -f concat -i concat.txt -c copy concat\%%g
)

could do it provided your mp4 file matches black.mp4

[sheeracali]

this could add the black video to the end of all MP4s in a given folder? Do I just put the directory in place of *.mp4 ?

[videobruger]

Do I just put the directory in place of *.mp4 ?

No. You make a batch file say concat.bat with the code above. Then run it in a command shell and all the mp4 file in the folder will have the black video added.

And again: provided your mp4 file matches black.mp4